Chapter 4: Canine Influenza, 2nd Edition 2 CE Hours
Expiration Date : November 18, 2028 Course overview
This course is intended to educate general practice veterinarians about canine influenza. The course will highlight background information on influenza viruses in general before focusing exclusively on canine influenza. Learning objectives After completing this course, the learner will be able to: Describe the classification system used for influenza viruses. Identify the primary reservoir of influenza viruses. Describe the history of canine influenza in the United States. List current circulating canine influenza strains in the United States.
Topics to cover include transmission, clinical signs, diagnosis, treatment, and preventative strategies (including vaccination).
Describe the transmission of canine influenza virus. List the clinical signs of canine influenza virus. Explain diagnostic tests used in the diagnosis of canine influenza virus. Outline an approach to the treatment of canine influenza virus. Describe strategies used to prevent canine influenza infection.
INTRODUCTION
threat of the disease and recommended measures to protect pet dogs. Since these initial outbreaks, both strains of canine influenza (H3N8 and H3N2) have continued to circulate in pet dogs. Canine influenza often slips from dog owners’ awareness for a period of time, before resurfacing in the form of unpredictable outbreaks. This course is designed to provide veterinarians with information on the historical background and epidemiology of canine influenza, as well as practical information related to diagnosis, treatment, and prevention. With this information, veterinarians will be more prepared for canine influenza outbreaks in their community and also more prepared to educate dog-owning clients and address their concerns. Influenza viruses are relatively host-specific, often remaining within a single host species. However, influenza infections are occasionally observed to jump between species. The natural host of influenza A is thought to be migratory birds, where it typically resides in the gastrointestinal epithelium. Because many strains of influenza virus cause no signs of disease in avian hosts (although highly pathogenic avian influenza strains can and do lead to clinical signs in some affected birds), influenza A viruses are easily spread worldwide and distributed in fecal material by migratory waterfowl. (Moyer, 2011) When these influenza viruses pass from their hosts to other species, the cross-species jumps can have important public health implications. Recent examples of these cross-species jumps in influenza include cases of highly pathogenic avian H5N1 viruses (“bird flu”) and swine origin H1N1 virus (“swine flu”) in the human population, as well as the 2024 jump of H5N1 from birds to cattle (and other species). (Landolt, 2011) (Burrough et al., 2024) In veterinary medicine, however, there have been two known cross-species jumps in influenza that have introduced canine influenza into our canine population. These species jumps occurred as two discrete events, but they led to the establishment of canine influenza that has become endemic in domestic dogs.
Canine influenza virus has been present in the United States canine population for more than 20 years. The virus was initially noted as a cause of respiratory disease outbreaks among racing greyhounds in 2004; at this time, it was noted to cause significant fatalities in racing greyhound kennels. This initial canine influenza outbreak was caused by a strain known as H3N8, and that strain of canine influenza has continued to circulate in the United States since 2004. In spring 2015, however, a new outbreak of respiratory disease was noted in Chicago. This outbreak was determined to be caused by a different strain of canine influenza, H3N2. The emergence of the H3N2 strain of canine influenza brought this disease back to the forefront in the minds of many dog owners, and veterinarians began receiving frequent questions from clients regarding the Influenza virus: General background Influenza viruses are single-stranded RNA viruses belonging to the family Orthomyxoviridae . These viruses are present in a number of animal species. Influenza viruses are known to cause varying clinical signs depending on the individual virus strain and the species infected. Influenza viruses are classified based on a number of characteristics that are unique to each strain of the virus. The first classification of influenza viruses is type. Each virus type is labelled by a letter: A, B, or C. These influenza types differ based on both structural characteristics and epidemiology. Influenza A viruses are the most-commonly discussed influenza viruses. They exist in a wide variety of species and are also the major contributors to human disease, both epidemics and pandemics. Influenza types B and C are found only in humans, and they are typically associated with less significant disease even within the human population. Influenza A viruses are then further divided into subtypes, based on two proteins that are found on the surface of the viral lipid envelope: hemagglutinin (HA) and neuraminidase (NA). The antigenic properties of these two proteins are each labeled by number, and these numbers define the influenza subtype. Currently, there are 16 HA subtypes (H1- H16) and 9 NA subtypes (N1-N9) that have been defined. (Moyer, 2011)
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Book Code: VFL1526
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